The present invention relates to ear tubes. In particular, the present invention relates to tubes for draining fluid through the eardrum and methods of inserting the tubes.
Typically, pressure within the middle ear is regulated by the Eustachian tube. Whenever the pressure within the middle ear is greater or less than the surrounding atmosphere, the Eustachian tube opens to equalize pressure. If the Eustachian tube is not functioning properly, the pressure within the middle ear tends to drop. The negative pressure in the middle ear draws fluid from the surrounding tissue and causes fluid to accumulate in the middle ear. This fluid causes swelling and infections within the middle ear.
In order to drain and ventilate the middle ear, ear tubes can be used. The tubes equalize pressure with the surrounding atmosphere, thereby eliminating the accumulation of fluid and reducing the risk of infection. To install a tube, a small incision is cut in the tympanic membrane, commonly called the ear drum, and the tube is inserted through the incision.
There are various types of ear tubes. One type of tube is formed as a shank with a trailing flange. This type of tube tends to fall out of the ear after a short period of time. Another type of tube, commonly called a T-tube on account of its shape, rarely falls out spontaneously, but requires removal by a physician. The T-tube has a flange that resiliently opens upon insertion through the ear drum, much like a toggle bolt. Unfortunately, the T-tube suffers from several disadvantages. The T-tube tends to leave a perforation in the eardrum about 25% of the time, which is considerably more than other types of tubes. The flange of the T-tube unfolds at an angle of 90° to the axis of the tube. These arms tend to “tent up” the eardrum and erode through the ear drum, causing a perforation. The reason for this “tenting-up” is that the eardrum is not flat, as sometimes thought, but has a complex curved shape such that the shape of a conventional T-tube puts undo pressure on the eardrum. Moreover, the T-tubes tend to shift and align themselves across the ear canal or block the tube, thereby making it difficult to see down the lumen of the tube to determine if the tube is obstructed. Additionally, the T-tubes tend to become obstructed with a plug of desiccated fluid or blood.
Yet another disadvantage of these T-tubes is the need for special instruments for inserting the tubes. During the insertion of the T-tubes, instruments are required to keep the arms of the T-tubes in alignment before the tube is pushed through the tympanic membrane. The insertion instruments are often difficult to operate and can cause the overall draining process to be both lengthy and tedious.
Therefore, there is a need for an improved ear tube that can be inserted without the use of special instruments and that stays in place unless removed, but does not tend to cause permanent perforations in the ear drum and that stays perpendicular to the ear drum and that can be readily cleared if it becomes obstructed.